Hydraulic presses rated for pressures up to 55 tons have been known. As shown in FIG. 1, these conventional presses include a pair of legs 11, 12 mounted on a pair of feet 13, 14 connected at the bottom by a cross brace 15. At the top of the legs, a head piece 16 is permanently connected (as by welding) to the two legs and provides the resistance for the hydraulic press. A bed 17 extends transversely across the legs and is positioned about midway between the head 16 and the feet 13, 14 and is carried by pins 18 that engage both the bed 17 and the legs 11, 12 at the opposite ends of the bed. The bed 17 carries the work piece to which the pressure is to be applied by the press. The bed 17 typically is reinforced at each opposite end of the bed 17 by a diagonally disposed spacer plate 19.
In a conventional press shown in FIG. 1 for example, each of the legs 11, 12, head piece 16, and bed 17 is formed of channel steel. The head 16 is formed by two lengths of channel steel 20 wherein each one is welded at each of its opposite ends to the upper end of each of the legs 11, 12. One length 20 is welded in the front of the press, and the other length 20 is welded in the back. Similarly, the bed 17 is formed by two lengths of channel steel 21 opposed to one another and joined at their opposite ends by welding the spacer plates 19 between them.
The gauge of the steel that is used depends upon the pressure rating of the press. For example, a conventional press rated at 55 tons typically would use 5 gauge channel steel for the legs 11,12, the lengths 21 forming the bed 17 and the lengths 20 forming the head 16. Conventional presses rated at 20 to 30 tons typically would use 9 gauge channel steel for the legs 11,12, the lengths 20 forming the head 16, and the lengths 21 forming the bed 17.
As shown in FIG. 1 for example, some conventional press designs have a carriage 22 that carries a hydraulic powered ram 24. As is conventional, the carriage 22 can be provided with one or more pairs of telescoping tubes 23 that guide the vertical movement of the carriage 22. In other designs such as shown in U.S. Pat. No. 4,283,825, which is hereby incorporated herein by this reference, the carriage 60 is guided by a pair of guide sleeves 63, 65, one being disposed at each opposite end of the carriage 60 and surrounding each leg.
The cost of shipping these conventional presses from the manufacturer to the customer depends on the volume occupied by the shipping carton and the weight of the press. Because the head 16 is welded to the legs and defines the overall width of the conventional press, the size of the shipping carton cannot be smaller than the width of the press. A conventional 55 ton press usually must be carried on a separate wooden pallet for each press. A shipping pallet holds about four conventional 30 ton presses or 20 ton presses, and about six conventional 12 ton presses usually can be shipped on a pallet. The shipping weight for a typical conventional press rated at 55 tons is about 480 pounds. Similarly, the shipping weights for a conventional 30 ton press is about 235 pounds, and 220 pounds for a conventional 20 ton press. A conventional 12 ton press has a shipping weight of about 80 pounds.
It is a principal object of the present invention to provide an hydraulic press that is lighter than conventional presses with the same pressure rating.
It is also a principal object of the present invention to provide an hydraulic press that has a more compact shipping volume than conventional presses with the same pressure rating.
It is a further principal object of the present invention to provide an hydraulic press that is less expensive to manufacture than conventional presses with the same pressure rating.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, an hydraulic press includes a pair of spaced apart, vertically extending legs, a head member having each one of its opposite ends connected to the top end of one of the legs, a hydraulic cylinder having one end connected to the head, and a bed disposed transversely between the two legs and configured so that the operator can selectively slide the bed vertically along the length of the legs.
Each leg is formed of a length of C-channel steel in which the tab portions are drilled with spaced apart aligned holes along the lower half of each leg. A foot member is removably connected to the bottom end of each leg, and a cross-brace is removably connected to each foot member.
The head member has a transverse cross-sectional shape resembling the letter U and defines a base section and a pair of opposed side sections. Each side section is configured and disposed to extend at a right angle from the base section. The upper portion of each side section further defines a lip that is disposed in a plane that is parallel to the plane of the base section and perpendicular to the plane of each side section. The head member is desirably formed as a unitary sheet of steel that is rolled into the generally U-shaped transverse cross-sectional configuration with the lips on the upper portions of the side sections. Each end of the head member is removably attached to the upper portion of one of the legs. This typically is accomplished by one or more threaded bolts and threaded nuts extending transversely through pre-drilled holes that are aligned in the upper portions of the legs and the ends of the head member. A reinforcement channel is disposed to extend transversely on the interior surface of the base section of the head member and has its ends welded to the interior surfaces of the side sections.
The bed member includes a pair of lengths of C-channel steel that are disposed in opposition to one another to form a front panel and a back panel. The upper and lower tabs of the C-channel are disposed to face away from the tabs on the opposed length of C-channel. These panels are permanently connected by a pair of spacer plates disposed symmetrically between the mid-portions of the front and back panels. A front breast plate is permanently attached to the front panel of the bed. A rear plate is permanently attached to the back panel of the bed. At the opposite ends of the front and back panels of the bed, at least one pair of aligned holes is configured to receive a press pin therein. When the bed is mounted on the press, a press pin is received within each pair of aligned holes defined in each end of the front and back panels of the bed and extending through a pair of aligned corresponding holes defined in the tab portions of each leg. A handle is permanently attached to each end of the bed.
In an alternative embodiment of the press, a carriage member is disposed slidably between the opposed legs and oriented between the bed member and the head member. A pair of springs connects and biases the carriage to the head member. A means of guiding the carriage in vertical travel between the head member and the bed can also be provided and can take any of a number of forms that are conventional in the art.
The press of the present invention can be completely disassembled for packing in a shipping carton. Since the head is removably attached to the legs by one or more bolts at each end of the head section and upper portion of the legs, the width of the shipping carton is not defined by the width of the assembled press of the present invention. The disassembled press of the present invention occupies a much smaller volume than a fully assembled conventional press. Moreover, the gauge of steel that is required for the components of the press of the present invention is lighter than the gauge of steel that is used in a comparably rated conventional press. Accordingly, the press of the present invention is lighter in weight and occupies less shipping space than a comparably rated conventional press. Additionally, the use of bolts to connect the head member to the legs means that the press of the present invention is easier and less costly to build than a comparably rated conventional press.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.